How is a messages sent to a specific user after it has been registred by the BackEnd using Azure Notification Hubs

Question

The Backend code to send messages using Azure Notificaion Hub to a specific userId:

var hubClient = NotificationHubClient.CreateClientFromConnectionString(connectionString, hubName);

var notification = new Dictionary<string, string> {
    { "message", "New Message" }
};

var userIdTag = "userId:12345";

await hubClient.SendTemplateNotificationAsync(notification, userTag);

Register the userId using an api that is called by the app:

var hubClient = NotificationHubClient.CreateClientFromConnectionString(connectionString, hubName);

var installation = new Installation
{
    InstallationId = Guid.NewGuid().ToString(), //or use userId?
    PushChannel = deviceToken, //sent by app
    Tags = new List<string> { "userId:12345" }
};

await hubClient.CreateOrUpdateInstallationAsync(installation);

How is a message then sent to a specific userId, what work needs to be done on the Android app side in order for the message to be sent to a specific userId?

Answer 1

How is a message then sent to a specific userId, what work needs to be done on the Android app side in order for the message to be sent to a specific userId?

Workflow:

• Create an Android app and initialize < app request for FCM token from Firebase Cloud Messaging < By using onNewToken method in MyFirebaseMessagingService it will trigger FCM by this token will obtain < That token is sent to the backend server for registration with Azure Notification Hub < backend server receives the FCM token from the Android app < backend server uses the Azure Notification Hub SDK to register the FCM token with Azure Notification Hub < FCM token is associated with the appropriate user ID using tags < based on our Configuration we will get the success or failure of the registration process

Firebase Messaging Service :

import android.util.Log;
import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    private static final String TAG = "MyFirebaseMsgService";

    @Override
    public void onNewToken(String token) {
        Log.d(TAG, "Refreshed token: " + token);
        // Send the token to your backend server
        sendRegistrationToServer(token);
    }

    private void sendRegistrationToServer(String token) {
        // Send the token to your backend server
        // This is where you would make an HTTP request to your backend API to register the token with Azure Notification Hub
        // Your backend server should handle the registration and association with the user ID
    }

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        // Handle incoming FCM messages here
        // You can customize the behavior based on the message payload
    }
}

AndroidManifest.xml :

<service
    android:name=".MyFirebaseMessagingService"
    android:exported="false">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>

• Enable your android API for public messaging.

• Copy this server key to connect with the azure notification hub.

• Save the key as shown below.

Backend Code :

class Program
{
    private static string connectionString = "YourNotificationHubConnectionString";
    private static string hubName = "YourNotificationHubName";

    static async Task Main(string[] args)
    {
        string userId = "12345"; // Sample user ID
        string deviceToken = "YourDeviceToken"; // Sample device token obtained from the Android app

        await RegisterDeviceTokenAsync(userId, deviceToken);

        Console.ReadLine(); // Keep the console window open
    }

    static async Task RegisterDeviceTokenAsync(string userId, string deviceToken)
    {
        var hubClient = NotificationHubClient.CreateClientFromConnectionString(connectionString, hubName);

        try
        {
            // Create or update installation for the user
            var installation = new Installation
            {
                InstallationId = Guid.NewGuid().ToString(), // You can use InstallationId or any other identifier, such as userId
                PushChannel = deviceToken,
                Tags = new List<string> { $"userId:{userId}" }
            };

            await hubClient.CreateOrUpdateInstallationAsync(installation);

            Console.WriteLine("Installation created or updated successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error creating or updating installation: " + ex.Message);
        }
    }
}

• Or else you can place the device token in the above application, which we get from the android app.

We can also send a test notification from portal to our required UserID as shown in below.